There is a vehicle-body front structure in which a cross-member is coupled between front end portions of left and right front side members, radiator core sides are respectively provided between the front end portions of the left and right front side members and left and right both end portions of a radiator core upper, and the radiator core upper (a bulkhead lower) is provided to connect lower ends of the radiator core sides.
With this vehicle-body front structure, the bulkhead lower is divided into radiator core side connection portions and a bulkhead lower body portion. The shape of the bulkhead lower can be simplified (for example, see Japanese Unexamined Patent Application Publication No. 4-27675).
There may be a vehicle-body front structure in which, when an external force acts from the vehicle front side, a heat exchanger that is arranged at the vehicle front side is allowed to move to the vehicle rear side by a predetermined distance while the support state of the heat exchanger with respect to the vehicle body is maintained.
With this vehicle-body front structure, a lower end of a radiator is supported by a flange that extends from a bulkhead to the front side, and when a front collision occurs, the radiator can move to the rear side (for example, see Japanese Unexamined Patent Application Publication No. 2008-132960).
There may be a vehicle-body front structure in which a bracket protrudes from a radiator core support in the vehicle front-rear direction, and a vehicle mount pin of a heat exchanger is fixed to a fixing hole of the bracket.
With this vehicle-body front structure, a lower end of a radiator is supported by a flange that extends to the front side from a bulkhead, and the heat exchanger can be mounted at the vehicle front side or the vehicle rear side (for example, see Japanese Unexamined Patent Application Publication No. 2008-68689).
There may be a vehicle-body front structure including a radiator support upper that is arranged in an upper portion of an engine room extending in the vehicle width direction and supports an upper portion of a heat exchanger, and a radiator support lower that is arranged in a lower portion of the engine room and has a support surface for supporting the heat exchanger, the support surface being recessed to the vehicle lower side.
With this vehicle-body front structure, any of a large radiator and a small radiator can be mounted on the vehicle body by adjusting the depth of the recess of the support surface (for example, see Japanese Unexamined Patent Application Publication No. 2007-331440).
There may be a vehicle-body front structure including a radiator core support (a bulkhead) to which two types of heat exchangers including a radiator and a condenser arranged in the vehicle front-rear direction can be attached.
With this vehicle-body front structure, an additional bracket is provided for supporting a lower end of the radiator, and can provide various support forms of the heat exchangers (for example, see Japanese Unexamined Patent Application Publication No. 2005-349924).
There may be a vehicle-body front structure including a radiator core support (a bulkhead) configured to fix in a surrounding manner a support pin protruding from an upper end portion of a heat exchanger (a radiator) by an upper bracket provided at the radiator core support and a cap that is inserted into and fixed to the upper bracket in the front-rear direction. Also, an additional bracket is provided for supporting a lower end of the radiator.
With this vehicle-body front structure, various support forms for the heat exchanger can be provided. Also, since the support pin of the heat exchanger (the radiator) is fixed in a surrounding manner, the radiator can be easily detached (for example, see Japanese Unexamined Patent Application Publication No. 2007-237889).
There may be a vehicle-body front structure in which both sides of a radiator panel that holds a radiator are fixed to a pair of left and right side frames extending in the front-rear direction of a vehicle body, and both the ends of the radiator panel are coupled through reinforcing members extending in the vehicle width direction.
With this vehicle-body front structure, bulkhead sides of the radiator panel (a bulkhead) each are formed in an L shape, and hence by removing a center portion of a bulkhead lower, the weight of the vehicle body can be reduced (for example, see Japanese Unexamined Patent Application Publication No. 2006-192983).
There may be a vehicle-body front structure including left and right front side frames extending in the front-rear direction along wheel aprons that form side walls of an engine room, and a frame-shaped front end member (a bulkhead) that supports a radiator at front portions of the left and right front side frames. A bulkhead lower of the bulkhead is formed in a vertically overlaid manner.
With this vehicle-body front structure, the rigidity of the bulkhead can be provided (for example, see Japanese Unexamined Patent Application Publication No. 2005-47324).
With the vehicle-body front structure described in Japanese Unexamined Patent Application Publication No. 4-27675, the bulkhead lower is divided. However, since the bulkhead lower is divided, divided parts desirably have an added value such as providing rigidity that is proper for operation stability.
With the vehicle-body front structure described in any of Japanese Unexamined Patent Application Publication No. 2008-132960 and No. 2008-68689, the lower end of the radiator is supported by the flange extending to the front side from the bulkhead lower. However, if the lower end of the radiator is supported by the flange, a proper stroke for absorbing an impact load cannot be provided. In particular, if a large radiator is used and a condenser is provided at the front of the radiator, the above-described phenomenon more likely occurs.
With the vehicle-body front structure described in Japanese Unexamined Patent Application Publication No. 2007-331440, the recess for adjusting the height of the radiator is provided at the bulkhead lower. However, a second moment of area decreases at the portion of the bulkhead lower provided with the recess for adjusting the height of the radiator. The bulkhead lower is likely affected by bending deformation, and it is difficult to provide the rigidity of the bulkhead.
With the vehicle-body front structure described in any of Japanese Unexamined Patent Application Publication No. 2005-349924 and No. 2007-237889, the additional bracket is provided for supporting the lower end of the radiator. However, if the additional bracket is provided, this may increase the number of parts.
With the vehicle-body front structure described in Japanese Unexamined Patent Application Publication No. 2006-192983, the bulkhead sides each are formed in the L shape. However, if the bulkhead sides each are formed in the L shape and the radiator is supported by the L-shaped portions, a phenomenon may occur in which the L-shaped portions may be opened. Hence, the operation stability of the vehicle may be degraded.
With the vehicle-body front structure described in Japanese Unexamined Patent Application Publication No. 2005-47324, the bulkhead lower is vertically overlaid. However, if the bulkhead lower is vertically overlaid, the weight of the bulkhead may increase.
In the past, a sub-frame for supporting an engine was directly fixed and fastened to a frame member in the up-down direction, and thus the rigidity of the vehicle body was provided. The rigidity of the front portion of the engine was provided by the cross member at the front side of the rectangular sub-frame to prevent the operation stability from being affected by a road-surface condition during driving, and the rigidity of the bulkhead lower was not required to be so high.
However, in recent years, multiple engine types are frequently set by an expansion of variety of needs. In particular, if an engine with a large magnitude of oscillation, such as a V-6 engine is mounted, the sub-frame for supporting the engine is not directly fastened to the frame member in view of restriction in transmission of a vibration, but is attached through a mount, such as a rubber bush. It is difficult to provide the rigidity of the vehicle body at the front part of the vehicle body required for the operation stability by the sub-frame.
Meanwhile, various drive loads act during driving. In particular, a load in the left-right direction is input to the lower end portion of the bulkhead. To prevent the loads from affecting the operation stability, the bulkhead lower has to have a proper sectional area. Also, the vibration has to be reduced such that the frequency specific to the vehicle body is changed by providing the proper rigidity and resonance with the oscillation of the engine is avoided.
Further, if the load in the left-right direction is input to the bulkhead lower, it is known that the front wall of the bulkhead lower is pushed to the front side, a moment acts entirely on the bulkhead so as to reciprocate from an obliquely upper front side to an obliquely lower rear side, and a phenomenon in which a closed section formed by a hat section and its upper lid is deformed (called opening phenomenon) occurs.
That is, there is desired a structure that restricts the generation of vibration while providing the operation stability and that can handle change in size of a radiator caused by change of an engine by providing a radiator support function originally intended for a bulkhead, without an increase in number of parts or an increased in number of manufacturing steps.